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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
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Add m-esr52 at 52.6.0
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// For atomic operations on reference counts, see atomic_refcount.h.
+// For atomic operations on sequence numbers, see atomic_sequence_num.h.
+
+// The routines exported by this module are subtle. If you use them, even if
+// you get the code right, it will depend on careful reasoning about atomicity
+// and memory ordering; it will be less readable, and harder to maintain. If
+// you plan to use these routines, you should have a good reason, such as solid
+// evidence that performance would otherwise suffer, or there being no
+// alternative. You should assume only properties explicitly guaranteed by the
+// specifications in this file. You are almost certainly _not_ writing code
+// just for the x86; if you assume x86 semantics, x86 hardware bugs and
+// implementations on other archtectures will cause your code to break. If you
+// do not know what you are doing, avoid these routines, and use a Mutex.
+//
+// It is incorrect to make direct assignments to/from an atomic variable.
+// You should use one of the Load or Store routines. The NoBarrier
+// versions are provided when no barriers are needed:
+// NoBarrier_Store()
+// NoBarrier_Load()
+// Although there are currently no compiler enforcement, you are encouraged
+// to use these.
+//
+
+#ifndef BASE_ATOMICOPS_H_
+#define BASE_ATOMICOPS_H_
+
+#include "base/basictypes.h"
+#include "base/port.h"
+
+namespace base {
+namespace subtle {
+
+// Bug 1308991. We need this for /Wp64, to mark it safe for AtomicWord casting.
+#ifndef OS_WIN
+#define __w64
+#endif
+typedef __w64 int32_t Atomic32;
+#ifdef ARCH_CPU_64_BITS
+typedef int64_t Atomic64;
+#endif
+
+// Use AtomicWord for a machine-sized pointer. It will use the Atomic32 or
+// Atomic64 routines below, depending on your architecture.
+#ifdef OS_OPENBSD
+#ifdef ARCH_CPU_64_BITS
+typedef Atomic64 AtomicWord;
+#else
+typedef Atomic32 AtomicWord;
+#endif // ARCH_CPU_64_BITS
+#else
+typedef intptr_t AtomicWord;
+#endif // OS_OPENBSD
+
+// Atomically execute:
+// result = *ptr;
+// if (*ptr == old_value)
+// *ptr = new_value;
+// return result;
+//
+// I.e., replace "*ptr" with "new_value" if "*ptr" used to be "old_value".
+// Always return the old value of "*ptr"
+//
+// This routine implies no memory barriers.
+Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
+ Atomic32 old_value,
+ Atomic32 new_value);
+
+// Atomically store new_value into *ptr, returning the previous value held in
+// *ptr. This routine implies no memory barriers.
+Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr, Atomic32 new_value);
+
+// Atomically increment *ptr by "increment". Returns the new value of
+// *ptr with the increment applied. This routine implies no memory barriers.
+Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr, Atomic32 increment);
+
+Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr,
+ Atomic32 increment);
+
+// These following lower-level operations are typically useful only to people
+// implementing higher-level synchronization operations like spinlocks,
+// mutexes, and condition-variables. They combine CompareAndSwap(), a load, or
+// a store with appropriate memory-ordering instructions. "Acquire" operations
+// ensure that no later memory access can be reordered ahead of the operation.
+// "Release" operations ensure that no previous memory access can be reordered
+// after the operation. "Barrier" operations have both "Acquire" and "Release"
+// semantics. A MemoryBarrier() has "Barrier" semantics, but does no memory
+// access.
+Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr,
+ Atomic32 old_value,
+ Atomic32 new_value);
+Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
+ Atomic32 old_value,
+ Atomic32 new_value);
+
+void MemoryBarrier();
+void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value);
+void Acquire_Store(volatile Atomic32* ptr, Atomic32 value);
+void Release_Store(volatile Atomic32* ptr, Atomic32 value);
+
+Atomic32 NoBarrier_Load(volatile const Atomic32* ptr);
+Atomic32 Acquire_Load(volatile const Atomic32* ptr);
+Atomic32 Release_Load(volatile const Atomic32* ptr);
+
+// 64-bit atomic operations (only available on 64-bit processors).
+#ifdef ARCH_CPU_64_BITS
+Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64* ptr,
+ Atomic64 old_value,
+ Atomic64 new_value);
+Atomic64 NoBarrier_AtomicExchange(volatile Atomic64* ptr, Atomic64 new_value);
+Atomic64 NoBarrier_AtomicIncrement(volatile Atomic64* ptr, Atomic64 increment);
+Atomic64 Barrier_AtomicIncrement(volatile Atomic64* ptr, Atomic64 increment);
+
+Atomic64 Acquire_CompareAndSwap(volatile Atomic64* ptr,
+ Atomic64 old_value,
+ Atomic64 new_value);
+Atomic64 Release_CompareAndSwap(volatile Atomic64* ptr,
+ Atomic64 old_value,
+ Atomic64 new_value);
+void NoBarrier_Store(volatile Atomic64* ptr, Atomic64 value);
+void Acquire_Store(volatile Atomic64* ptr, Atomic64 value);
+void Release_Store(volatile Atomic64* ptr, Atomic64 value);
+Atomic64 NoBarrier_Load(volatile const Atomic64* ptr);
+Atomic64 Acquire_Load(volatile const Atomic64* ptr);
+Atomic64 Release_Load(volatile const Atomic64* ptr);
+#endif // CPU_ARCH_64_BITS
+
+} // namespace base::subtle
+} // namespace base
+
+// Include our platform specific implementation.
+#if defined(OS_WIN) && defined(ARCH_CPU_X86_FAMILY)
+#include "base/atomicops_internals_x86_msvc.h"
+#elif defined(OS_MACOSX) && defined(ARCH_CPU_X86_FAMILY)
+#include "base/atomicops_internals_x86_macosx.h"
+#elif defined(COMPILER_GCC) && defined(ARCH_CPU_X86_FAMILY)
+#include "base/atomicops_internals_x86_gcc.h"
+#elif defined(COMPILER_GCC) && defined(ARCH_CPU_ARMEL)
+#include "base/atomicops_internals_arm_gcc.h"
+#elif defined(COMPILER_GCC) && defined(ARCH_CPU_ARM64)
+#include "base/atomicops_internals_arm64_gcc.h"
+#elif defined(COMPILER_GCC) && defined(ARCH_CPU_MIPS)
+#include "base/atomicops_internals_mips_gcc.h"
+#elif defined(COMPILER_GCC) && defined(ARCH_CPU_PPC_FAMILY)
+#include "base/atomicops_internals_ppc_gcc.h"
+#else
+#include "base/atomicops_internals_mutex.h"
+#endif
+
+#endif // BASE_ATOMICOPS_H_